Uptake of noradrenaline in high altitude native's heart

Summary Uptake of³H-noradrenaline by the heart was studied with sections of isolated atria obtained from high or lowlanders. In native highlanders, affinity for³H-noradrenaline by human atria is more significant than in lowlanders. Furthermore, the Michaelis Menten constant is lower in high altitude native's heart.     

Inhibition of suppressor T-cell development following deoxyguanosine administration

The expression of immunodeficiency in patients with specific purine enzyme defects indicates a crucial role of the purine salvage pathway in the acquisition and expression of normal immune function. One current hypothesis links the failure of normal lymphocyte development in these diseases to the accumulation of deoxynucleotide triphosphates. In our studies of human in vitro IgM responses, we observed that antigen-induced T-suppressor cell activity was abrogated in the presence of micromolar concentrations of deoxyguanosine (dGuo). In contrast, more than 1,000-fold higher resistance to dGuo was found for both noin-proliferative T-helper cell activity and the differentiation and proliferation of the precursor B lymphocytes for direct haemolytic plaque forming cells (PFC). To determine whether these observations could have in vivo relevance, we monitored the generation of murine T-suppressor cells, capable of abrogating a primary IgM response. It was found that dGuo (but not guanosine) selectively inhibited the in vivo development of T-suppressor cells.     

Targeted integration of baboon endogenous virus in the BEVI locus on human chromosome 6

The infection of cultured human cells with baboon endogenous virus (BEV) frequently leads to an association of viral DNA with a specific genetic locus (termed BEVI, for baboon endogenous virus infection) on chromosome 6. Restriction endonuclease digestion of DNA from BEV-infected human cells and their derived somatic cell clones frequently revealed a common cellular DNA sequence in the proximity of one of the junctions between cellular DNA and the integrated virus. We propose that a short cellular DNA sequence, repeated on chromosome 6 and separated by unique DNA sequences, presents a high-affinity target for the integration of BEV in human cells.     

Identification of a protein encoded by the vpu gene of HIV-1

Human immunodeficiency virus 1 (HIV-1) is the aetiological agent of AIDS. The virus establishes lytic, latent and non-cytopathic productive infection in cells in culture. The complexity of virus-host cell interaction is reflected in the complex organization of the viral genome. In addition to the genes that encode the virion capsid and envelope proteins and the enzymes required for proviral synthesis and integration common to all retroviruses, HIV-1 is known to encode at least four additional proteins that regulate virus replication, the tat, art, sor and 3' orf proteins, as well as a protein of unknown function from the open reading frame called R. Close examination of the nucleic acid sequences of the genomes of multiple HIV isolates raised the possibility that the virus encodes a previously undetected additional protein. Here we report that HIV-1 encodes a ninth protein and that antibodies to this protein are detected in the sera of people infected with HIV-1. This protein distinguishes HIV-1 isolates from the other human and simian immunodeficiency viruses (HIV-2 and SIV) that do not have the capacity to encode a similar protein.